only read as much as fits inside of a GNUNET_Message

1 files changed, 4 insertions, 2 deletions

diff --git a/src/vpn/gnunet-vpn-helper.c b/src/vpn/gnunet-vpn-helper.c
index 1d0b1ad28..4a75182f9 100644
--- a/src/vpn/gnunet-vpn-helper.c
+++ b/src/vpn/gnunet-vpn-helper.c
@@ -48,6 +48,8 @@
 #ifndef _LINUX_IN6_H
 // This is in linux/include/net/ipv6.h.
 
+#define MAX_SIZE (65535 - sizeof(struct GNUNET_MessageHeader))
+
 struct in6_ifreq {
     struct in6_addr ifr6_addr;
     __u32 ifr6_prefixlen;
@@ -112,7 +114,7 @@ void setnonblocking(int fd) {/*{{{*/
 }/*}}}*/
 
 int main(int argc, char** argv) {
-        unsigned char buf[65600]; // 64k + 64;
+        unsigned char buf[MAX_SIZE];
 
         char dev[IFNAMSIZ];
         memset(dev, 0, IFNAMSIZ);
@@ -203,7 +205,7 @@ outer:
                                 }
                         } else if (write_stdout_possible && FD_ISSET(fd_tun, &fds_r)) {
                                 write_stdout_possible = 0;
-                                r = read(fd_tun, buf, 65600);
+                                r = read(fd_tun, buf, MAX_SIZE);
                                 if (r <= 0) {
                                         fprintf(stderr, "read-error: %m\n");
                                         shutdown(fd_tun, SHUT_RD);